British Transport Police has launched an appeal after a 17-year-old boy was robbed at knifepoint on the Tube.

The victim and his friend were approached by a man who told them he had a knife and demanded to see their phones while on a Hammersmith & City line train just before midday on Wednesday (November 4) last year.

Detective Constable Martin Coburn said: “As the train passed Wood Lane station, the man produced a knife and held it to the victim’s thigh and demanded his phone.

“Fearing for his safety, the victim handed his phone over. The robber left the train at Ladbroke Grove.”

Police have issued an image of a man they believe has information about the incident.

DC Coburn continued: “We work hard to ensure the Underground remains a safe environment, and I would like to reassure the public that incidents of this type are rare.

“I am keen to speak to the man in the picture as I believe he can help us with our enquiries. Please tell us who he is.”

Anyone with information is asked to contact British Transport Police on 0800 40 50 40, or text 61016, quoting reference 140 of 26/2/16.

Information can also be passed anonymously to the independent charity Crimestoppers on 0800 555111.